1. Field of the Invention
The present invention relates to firing equipment that can be operated under pressure charge or turbocharge, especially fluidized bed firing equipment for a steam generator.
2. Description of the Prior Art
German Pat. No. 30 04 848 Dibelius et al issued Nov. 10, 1983 and belonging to the assignee of the present invention discloses fluidized bed firing equipment of this general type, with this known firing eqiupment being characterized by the following features:
(a) the compressor is divided into two successively arranged individual compressors, with the first compressor being driven only by a gas turbine, and the second compressor being driven by independent power;
(b) a controllable air by-pass line is connected in parallel to the first compressor; and
(c) a controllable flue gas by-pass line having a flue gas cooler is connected in parallel to the gas turbine.
This combination of features of the heretofore known firing equipment solves the task of undertaking the supply of air to the fluidized bed firing equipment in such a way that at atmospheric operation only the devices required herefor operate, and that the supplemental devices required for turbocharged operation obtain their energy requirement that exceeds a minimum pressure necessary for this manner of operation nearly exclusively from the energy that is then available in the flue gas. During turbocharged operation, the flue gas is conveyed only to the turbine that drives the first compressor, while the second compressor is driven by an electric motor to provide the necessary quantity of air. During non-turbocharged operation, air is provided primarily by the second compressor, and the flue gas is conveyed to an air preheater disposed between the firing equipment and the second compressor, and to a chimney. Furthermore, to maintain the chimney inlet temperature and the production equilibrium, it is possible to control the air by-pass line of the first compressor and the flue gas by-pass line of the gas turbine in opposite directions in such a way that the pressure increase system is in a position to continuously supply the fluidized bed firing equipment up to the level of the highest design pressure.
However, by operating the second compressor with independent power, no optimum efficiency can be achieved with the heretofore known firing equipment, even during turbocharged operation.
An object of the present invention is to be able to achieve optimum efficiency.